reworked db logic based on iden3 pattern - allows for single storage location with prefixing

db/leveldb.go

@@ -0,0 +1,97 @@
+package db
+
+// modified from https://github.com/iden3/go-iden3/blob/master/db/leveldb.go
+
+import (
+	"encoding/json"
+
+	"github.com/syndtr/goleveldb/leveldb"
+//	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+)
+
+
+type LevelDbStorage struct {
+	ldb    *leveldb.DB
+	prefix []byte
+}
+
+func NewLevelDbStorage(path string, errorIfMissing bool) (*LevelDbStorage, error) {
+	o := &opt.Options{
+		ErrorIfMissing: errorIfMissing,
+	}
+	ldb, err := leveldb.OpenFile(path, o)
+	if err != nil {
+		return nil, err
+	}
+	return &LevelDbStorage{ldb, []byte{}}, nil
+}
+
+type storageInfo struct {
+	KeyCount int
+}
+
+func (l *LevelDbStorage) Info() string {
+
+	keycount := 0
+	iter := l.ldb.NewIterator(nil, nil)
+	for iter.Next() {
+		keycount++
+	}
+	iter.Release()
+	if err := iter.Error(); err != nil {
+		return err.Error()
+	}
+	json, _ := json.MarshalIndent(
+		storageInfo{keycount},
+		"", "  ",
+	)
+	return string(json)
+}
+
+func (l *LevelDbStorage) WithPrefix(prefix []byte) *LevelDbStorage {
+	return &LevelDbStorage{l.ldb, append(l.prefix, prefix...)}
+}
+
+func (l *LevelDbStorage) Get(key []byte) ([]byte, error) {
+	v, err := l.ldb.Get(append(l.prefix, key[:]...), nil)
+	if err != nil {
+		return nil, err
+	}
+	return v, err
+}
+
+func (l *LevelDbStorage) Put(key []byte, value []byte) error {
+	err := l.ldb.Put(append(l.prefix, key[:]...), value, nil)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (l *LevelDbStorage) Delete(key []byte) error {
+	err := l.ldb.Delete(append(l.prefix, key[:]...), nil)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (l *LevelDbStorage) Close() {
+	if err := l.ldb.Close(); err != nil {
+		panic(err)
+	}
+}
+
+func (l *LevelDbStorage) Iter() iterator.Iterator {
+	db := l.ldb
+	i := db.NewIterator(util.BytesPrefix(l.prefix), nil)
+	return i
+}
+
+func (l *LevelDbStorage) LevelDB() *leveldb.DB {
+	return l.ldb
+}
+